Electronic thermoelectric power factor and metal-insulator transition in FeSb2

TL;DR

This study demonstrates that a synthesis-induced metal-insulator transition in FeSb₂ significantly enhances its thermoelectric power factor, reaching record levels at low temperatures, due to correlated electron effects and subtle structural differences.

Contribution

It reveals how synthesis-induced MIT in FeSb₂ boosts thermoelectric performance, highlighting the role of correlated electrons and structural nuances in achieving high power factors.

Findings

Record high thermoelectric power factor of ~8000 μWK$^{-2}$cm$^{-1}$ at 28 K.

MIT induced by subtle structural differences enhances electrical conductivity.

Correlated electron model explains large thermopower in FeSb₂.

Abstract

We show that synthesis-induced Metal -Insulator transition (MIT) for electronic transport along the orthorombic c axis of FeSb$_{2}$ single crystals has greatly enhanced electrical conductivity while keeping the thermopower at a relatively high level. By this means, the thermoelectric power factor is enhanced to a new record high S$^{2}$$\sigma$ $\sim$ 8000 $\mu$WK$^{-2}$cm$^{-1}$ at 28 K. We find that the large thermopower in FeSb$_{2}$ can be rationalized within the correlated electron model with two bands having large quasiparaticle disparity, whereas MIT is induced by subtle structural differences. The results in this work testify that correlated electrons can produce extreme power factor values.